High Efficiency Water Purification System

• US 20120145636A1
• Filed: 12/27/2011
• Published: 06/14/2012
• Est. Priority Date: 12/10/2010
• Status: Active Grant

• Current Assignee: Water Intellectual Properties, Inc.
• Original Assignee: Water Intellectual Properties, Inc.
• Inventors: Hooley, Joseph, Kovacs, William E.
• Granted Patent: US 8,691,095 B2
• Time in Patent Office: Days
• US Class Current: 210/652
• CPC Class Codes: B01D 2311/08 Specific process operations in the concentrate stream
• CPC Class Codes: B01D 2311/25 Recirculation, recycling or bypass, e.g. recirculation of concentrate into the feed
• CPC Class Codes: B01D 2311/2512 to feed side
• CPC Class Codes: B01D 2317/022 Reject series
• CPC Class Codes: B01D 2317/04 Elements in parallel
• CPC Class Codes: B01D 61/025 Reverse osmosis; Hyperfiltration
• CPC Class Codes: B01D 61/026 comprising multiple reverse osmosis steps
• CPC Class Codes: B01D 61/04 Feed pretreatment
• CPC Class Codes: B01D 61/58 Multistep processes
• CPC Class Codes: C02F 1/001 Processes for the treatment of water whereby the filtration technique is of importance C02F1/44 takes precedence; construction of filters in general B01D24/00 - B01D41/00
• CPC Class Codes: C02F 1/441 by reverse osmosis
• CPC Class Codes: C02F 2103/02 Non-contaminated water, e.g. for industrial water supply
• CPC Class Codes: C02F 2209/40 Liquid flow rate
• CPC Class Codes: C02F 2301/08 Multistage treatments, e.g. repetition of the same process step under different conditions

Abstract

A high efficiency water purification system is provided incorporating recovery of a portion concentrate wastewater associated with the reverse osmosis unit. This reduces the overall volume of concentrate wastewater requiring discharge/disposal by reusing the purified concentrate of a concentrate recovery units as RO feed water. Initial feedwater is pressurized and passed through an RO membrane, and separated into a permeate flow and a concentrate flow. A portion of the higher pressure concentrate is then directed to an additional set of thin film composite membranes (concentrate recovery membranes). The concentrate recovery membranes are arranged in an array such that the concentrate pressure is adequate to provide the force required to drive the concentrate through the recovery system membranes. The permeate produced by the concentrate recovery system is directed back to the feed of the primary RO unit; thereby, reducing the volume of raw feed water required for system operation.

Claims

1. A water purification systems comprising:

a feedwater source;

a primary reverse osmosis unit treating a first input and having a first permeate discharge and a first concentrate discharge;

at least one concentrate recovery unit in fluid communication with said first concentrate discharge in which at least a portion of said concentrate discharge is further separated into a second permeate discharge and a second concentrate recovery;

a flow restriction mechanism within said permeate flow; and

a flow modulation stop limit to prevent total cessation altogether of primary permeate flow;

wherein both said second concentrate recovery and said feedwater source are in fluid communication with said first input; and

wherein the combination of said first permeate recovery and said second permeate recovery is capable of continuous recovery of at least 80% of said feedwater source.

2. The water purification system of claim 1, wherein said feedwater source is selected from the group consisting of:

municipal water sources;

industrial water sources; and

tertiary water sources.

3. The water purification system of claim 2, wherein said primary reverse osmosis unit comprises at least one thin film recovery membrane.

4. The water purification system of claim 3, further comprising:

said concentrate recovery unit comprising a plurality of composite reverse osmosis membrane modules arranged in parallel, and

each said module having a permeate discharge in combination with each other and forming said second permeate discharge, and wherein each module further has a concentrate discharge in combination with each other and forming said second concentrate discharge;

wherein said first concentrate discharge is in driven in fluid communication with said concentrate recovery unit with the urging force of the concentrate pressure of said primary reverse osmosis unit and without the input of additional energy.

5. The water purification system of claim 3, wherein said concentrate recovery unit further comprises at least one additional reverse osmosis stage in series for separating the collected permeate form said plurality of composite reverse osmosis membrane modules arranged in parallel.

6. The water purification system of claim 5, wherein said additional reverse osmosis stage further comprises a plurality of additional reverse osmosis elements.

7. A water purification systems of claim 1, wherein said primary reverse osmosis unit is operated at a pressure in the range of 200-400 psig.

8. The water purification system of claim 7, wherein said concentrate recovery is operated at a pressure in the range of 200-300 psig.

9. The water purification system of claim 2, wherein said feedwater source is pre-treated by filtering and otherwise removing materials known to be detrimental to RO membrane operation.

10. The water purification system of claim 1, wherein said concentrate recovery system is adapted to be capable of retrofit onto existing RO installations.

11. The water purification system of claim 1, wherein said flow restriction mechanism can be modulated inversely proportional to inlet temperature or directly proportional to inlet pressure, or otherwise modulated based upon measured flowrates of primary permeate flow or primary concentrate flow.

12. The water purification system of claim 1, further comprising means for decreasing membrane fouling through the direction injection of antiscalant or acidic chemicals in relatively small concentration into and in relative proportion with the primary concentrate discharge.

13. The water purification system of claim 12, wherein said means for decreasing membrane fouling further comprises injection fo antiscalant as a calculated and controlled function based upon determination of the Langelier Saturation Index of the water within the system.

14. The water purification system of claim 3, further comprising a system for an in situ “

flush”

of primary permeate flow through the secondary recovery system.

15. The water purification system of claim 12, further comprising a system for an in situ “

flush”

of primary permeate flow through the secondary recovery system.

16. A process to recover a portion of the concentrate wastewater associated with the reverse osmosis unit for reducing the overall volume of concentrate wastewater requiring discharge/disposal by reusing the purified concentrate of a concentrate recovery units as RO feed water, said process comprising:

a. obtaining an initial feed water inlet;

b. pressurizing said feedwater and passed said feedwater through a thin film composite reverse osmosis membrane to create a separate first permeate flow and a first concentrate flow;

c. restricting the permeate flow in a manner that prevents total cessation altogether of primary permeate flow;

d. directing said first concentrate flow to an additional set of thin film composite membranes (concentrate recovery membranes), wherein said concentrate recovery membranes are arranged in an array such that the concentrate pressure is adequate to provide the force required to drive the concentrate through the recovery system membranes; and

e. directing the permeate produced by the concentrate recovery system back to the feed of the primary RO unit;

thereby, reducing the volume of raw feed water required for system operation.

17. The process of claim 16, wherein a concentrate flow rate is controlled by a second flow control valve and is discharged as a wastewater.

18. The process of claim 16, wherein said concentrate recovery system is operated at between 30-60% recovery depending on the feed water characteristics as limited by sparingly soluble salts which can foul the reverse osmosis membranes.

19. The process of claim 16, adapted to be retrofitted onto existing RO installations.

20. In a process for computerized model for designing a reverse osmosis water purification system utilizing ROSA (Reverse Osmosis System Analysis) design software as provided by DOW®

and for modeling FILMTEC™

reverse osmosis membranes, the improvement comprising;

the process of claim 16 to recover a portion of the concentrate wastewater associated with the reverse osmosis unit for reducing the overall volume of concentrate wastewater requiring discharge/disposal by reusing the purified concentrate of a concentrate recovery units as RO feed water;

wherein a single design calculation is performed for said primary or said secondary recovery without separate calculations of said primary and said secondary recovery or iteration between separate calculations for said primary and said secondary recovery, respectively.